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Show 1877.] BURSA FABRICII IN BIRDS. 305 Prosector's department have given me opportunities for examining this organ in a considerable number of species of birds of various orders ; and though I regret to say m y investigations have not turned out so satisfactorily as regards taxonomic characters as I had hoped, I venture to bring such results as I have obtained before the Society this evening. As the subject of the bursa Fabricii has hardly attracted any notice in this country since the days of Harvey, I have added to m y own notes a brief resume of the most important observations and opinions as regards its structure and functions that have been brought forward by foreign anatomists. The organ in question seems first to have been noticed by the naturalist whose name it bears, Fabricius of Acquapendente. In his treatise ' De formatione ovi et pulli'1, p. 5, he says : - " Tertium quod in podice est adnotandum est duplex vesicula quae in ima ejus parte ad os pubis supereminet, et conspicua exteriorque apparet, si-mulatque uterus jam propositus conspectui sese offert: quse cum sit pervia, ita ut ab ano ad ipsum uterum et ab utero in ipsam, ut puta superius, infra foramen pateat, ex altero autem extremo clausa sit, hunc existimavimus esse locum, in quern gallus semen immittit por-rigitque ut inibi servetur." From this and other passages in his works it is clear that he considered its function that of a receptacu-lum seminis in the female ; its use in the male, on such a theory, he does not explain. Harvey, in his work 'De Generatione Animalium ' (London, 1651), as quoted in the Sydenham Society's translation of his works (1847, p. 183), refutes Fabricius's ideas on this point. " The foramen into which Fabricius believes the Cock to inject his fluid, is discovered between the orifices of the vulva and the rump. I, however, deny any such use to this foramen ; for in young chickens it is scarcely to be seen, and in adults it is present indifferently in males and females. It is obvious therefore that it is both an extremely small and obscure orifice, and can have no such important function to fulfil; it will scarcely admit a fine bristle and needle, and it ends in a blind cavity ; neither have I ever been able to discover any spermatic fluid within it, although Fabricius asserts that this fluid is stored up there even for a whole year, and that all the eggs contained in the ovary may be thence fecundated, as it is afterwards stated." Harvey, however, fell into error in asserting that in "young chickens it was scarcely to be seen ;" as we shall afterwards see, it is developed more in young than adult birds. This fact was first pointed out by Tannenberg in 1789, in his disquisition ' Circa geni-tales partes mascularum avium' (Gottingse), and has subsequently been recognized by most authors who have written on the subject (vide Cuvier2, Milne-Edwards3, and Gegenbaur4). Barkow, in a paper " O n the Cloaca of birds" in Meckel's 'Archiv '*, describes its condition in specimens he had examined of the Fowl, Duck, 1 Hieronymi Fabricii ab Aquapendente opera anatomica. Patavii, 1625. 2 Lecons d'Anatomie comparee, 2nd ed. vol. viii. p. 276. 3 Physiologie et Anatomie comparee, vol. viii. p. 514, and vol. vii. p. 347. 1 Vergleichende Anatomie, p. 799, note. 5 Archiv, 1829, p. 443 et seq. PROC. ZOOL. Soc-1877, No. XX. 20 |